300 E AC Problem
Thread Starter
Junior Member
Joined: Dec 2006
Posts: 60
Likes: 1
From: South River NC
300 E AC Problem
AC was working early fall, now it doesn't. The compressor is not coming on. The fuses are all good....even the Over Voltage Relay fuse. Obviously no power to the compressor, because the clutch won't engage even when pushed against when the engine is running.
I checked the grounds...they're fine.
It could be the (AMP??? can't remember the name) back behind the OVR, but the engine runs great with no fuel related problems.
How can I jump the compressor? Which wires?
Shadow, you still out there? Don't really need AC right now, but I want everything working, and I think it's good to run the AC occasionally.
Shadow, come on back.......you the man!!!
I checked the grounds...they're fine.
It could be the (AMP??? can't remember the name) back behind the OVR, but the engine runs great with no fuel related problems.
How can I jump the compressor? Which wires?
Shadow, you still out there? Don't really need AC right now, but I want everything working, and I think it's good to run the AC occasionally.
Shadow, come on back.......you the man!!!
Newbie
Joined: Jul 2007
Posts: 20
Likes: 0
From: Rhode Island
Mercedes 300e 1986
If you jump the two wires together which go into the pressure sensor on the dryer located just behind your drivers side head light.. If it does come on this could be an indication that there is not enough pressure (eg leak somewhere)in the system and it needs to be refilled or that the pressure sensor is bad.. Think mine cost around $30 from mercedes to replace however turns out I had a slow leak!
Thread Starter
Junior Member
Joined: Dec 2006
Posts: 60
Likes: 1
From: South River NC
Excellent guys!
First, I think my AC controls are OK as they still direct the flow to the selected area.
I'm going to go and jump the "low pressure switch" now. I'll be back in 5 minutes.
First, I think my AC controls are OK as they still direct the flow to the selected area.
I'm going to go and jump the "low pressure switch" now. I'll be back in 5 minutes.
Thread Starter
Junior Member
Joined: Dec 2006
Posts: 60
Likes: 1
From: South River NC
I jumped the low pressure switch...........no luck
I jumped the switch right next to it........no luck
I pulled the OVR, fuse is still good
Which box is the MAS, the one toward the rear of the car or the one in the front? There are 2 boxes back by the OVR which are about the same size. I'm guessing the front one is the MAS.
The one in the front has the work "KICKDOWN" on it.
Any ideas, thanks guys.
I jumped the switch right next to it........no luck
I pulled the OVR, fuse is still good
Which box is the MAS, the one toward the rear of the car or the one in the front? There are 2 boxes back by the OVR which are about the same size. I'm guessing the front one is the MAS.
The one in the front has the work "KICKDOWN" on it.
Any ideas, thanks guys.
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Member
Joined: Aug 2007
Posts: 146
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1986 300E
I had this problem a while back. Not sure if itll help but it worked for me.
Open up the fuse box, then take off the plate with the fuses on it. and you have a mess of wires. I jiggled the wires around and found that one of the connections in there was loose. tightend a few screws (One was in a lil black box) and cleaned out anything that looked like it wo uld help with some Electrical cleaner.
Good luck
Open up the fuse box, then take off the plate with the fuses on it. and you have a mess of wires. I jiggled the wires around and found that one of the connections in there was loose. tightend a few screws (One was in a lil black box) and cleaned out anything that looked like it wo uld help with some Electrical cleaner.
Good luck
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Thread Starter
Junior Member
Joined: Dec 2006
Posts: 60
Likes: 1
From: South River NC
Thanks Flood, I've wiggled and jiggled all the fuses and wires. Had all the fuses out and back in.
I'm leaning toward the MAS, as I've read it's a common problem.
There are 2 connector plugs on the AC compressor. One has 2 wires, the other has 3.
Anyone know which wires powers the clutch? Why so many wires going to the compressor?
Love the good old days when you could put power to AC clutch on the 2 terminals.
I'm leaning toward the MAS, as I've read it's a common problem.
There are 2 connector plugs on the AC compressor. One has 2 wires, the other has 3.
Anyone know which wires powers the clutch? Why so many wires going to the compressor?
Love the good old days when you could put power to AC clutch on the 2 terminals.
MBWorld Fanatic!
Joined: Aug 2002
Posts: 1,005
Likes: 33
From: Germany
'00 S320 W220, '98 A160 W168/ sold in 2005 '86 260 E W124 '90 260E W124
The clutch has 2 wires and in my car one of the wire was rotten. Very hard to find and even worse to replace. The wires enter the clutch on the lower end of it and disappear inside the clutch running through an "insulator block". I guess the best way would be to have the car on a car lift and check from the bottom.
